<?php
$car = array(
    ['id' => 612, 'name' => 'bus', 'weight' => 300, 'capacity' => 22],
    ['id' => 1580, 'name' => 'taxi', 'weight' => 210, 'capacity' => 5],
    ['id' => 300, 'name' => 'coach', 'weight' => 550, 'capacity' => 86],
);
print_r( $car );
print $car[0]['capacity'];
$car[] = ['id' => 105, 'name' => 'motorbike', 'weight' => 100, 'capacity' => 2];
$car[2]['name'] = 'truck';
$car[2]['weight'] = 350;
print_r( $car[2] );
unset( $car[0]['weight'] );
unset( $car[1] );
print_r( $car );
echo "bus的承载量是" . $car[0]['capacity'];
//遍历